<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #box {
            width: 200px;
            height: 200px;
            background-color: #6ff;
        }
    </style>
</head>

<body>
    <div id="box"></div>
</body>
<script>
    /* var box = document.getElementById("box");
    var x=1;
    box.onclick = function () {
        if (x % 2 == 1){
            box.style.background = "#ff6";
            box.style.width = "400px";
            box.style.height = "400px";
        } else if(x%2==0){
            box.style.background = "#6ff";
            box.style.width = "200px";
            box.style.height = "200px";
        }
        x++;  
        // console.log(x);      
    } */

    var str = "这是一个字符串";
    var num = 10, nul = null, x;
    var arr=[1,2,3,4];
    console.log(str,num,nul,x,arr,typeof str);

</script>

</html>